Many manufactured parts, such as ceramic parts, require one or more forms of heating or firing, which are carried out in an oven using radiant heat and some form of convection, be it incidentally occurring due to temperature differences in the oven, or artificially and intentionally generated. The parts are laid on a bed of sand in the oven, which serves to support the parts and to radiate heat toward the parts. The bed of sand also detrimentally insulates a large portion of the parts against contact with convecting gas within the oven. As a result, the surfaces of the parts are not heated or fired uniformly. Temperature differentials within the parts can cause cracking or other defects. Further, during some processes, gases within the parts are released, and the sand contacting a large surface area of the parts inhibits this gas release. The trapped gases can cause unwanted voids, or build pressure within the parts that causes cracks or other defects.